Objectives: Studies have implied the presence of Helicobacter species in the human liver. The possible relationship between the presence of Helicobacter species in the non-cirrhotic liver of patients with hepatocellular carcinoma (HCC) and the detection of Helicobacter species in their stomach was explored.
Patients and methods: A 16S rDNA-based polymerase chain reaction (PCR) followed by DNA sequence analysis of the obtained PCR fragments was performed on 51 surgically obtained non-cirrhotic liver specimens and 14 gastric samples.
Results: Analysis indicated a significant difference in the presence of Helicobacter-species-specific DNA in the liver of patients with HCC compared with controls. Sequence analysis of these PCR products obtained from HCC patients indicated that they were related most closely to the 16S rDNA sequence of Helicobacter pylori but that they always differed at the same two positions. This same aberrant Helicobacter-species-specific 16S rDNA could be isolated in gastric samples of patients with HCC.
Conclusion: These data suggest that gastric colonization with a specific subset of Helicobacter strains is associated with the induction of HCC, either directly via colonization of the liver or indirectly, e.g. via secretion of specific toxins by Helicobacter residing in the stomach.